Conrad IV of Germany

Conrad IV of Germany (25 April 1228-21 May 1254) was King of Jerusalem from 25 April 1228 to 21 May 1254, succeeding Isabella II of Jerusalem and preceding Conradin; King of the Romans from May 1237 to 21 May 1254, succeeding Henry (VII) of Germany and preceding William II of Holland; and King of Sicily from 13 December 1250 to 21 May 1254, succeeding Frederick II of Germany and preceding Conradin.

Biography
Conrad was born on 25 April 1228, the only surviving son of Frederick II of Germany and Isabella II of Jerusalem. On his mother's death, he inherited the Kingdom of Jerusalem, and he succeeded his rebellious half-brother Henry (VII) of Germany as Duke of Swabia in 1235 when Frederick revoked Henry's title. The emperor had him declared King of the Romans in 1237 to guarantee his succession to the throne on his father's death, and he succeeded his father in 1250 on his death. He had to fight against William II of Holland to restore stability to Germany, which had been destroyed by papal intervention in German politics; he defeated William and his Rhenish allies in 1250, but he was defeated by William in 1251. Conrad decided to invade Italy to add more lands to the Holy Roman Empire, conquering Naples in October 1253. However, he could not subdue the pope's supporters, and he died of malaria at Lavello, Lucania in 1254.